mongez-copper-log

name

mongez-copper-log

description

Themed CLI logger with `debug` / `info` / `success` / `warn` / `error` levels, colored symbol prefixes, level filtering, and a custom output stream. Errors serialize stack traces; plain values pass through `JSON.stringify` for structured printing. TRIGGER when: code imports `log`, `createLogger`, `Logger`, `LogLevel`, or `LoggerOptions` from `@mongez/copper`; user asks "how do I print colored info / warn / error logs in a CLI / silence info messages in quiet mode / log to stderr"; replacing `consola`, `signale`, `ansi-colors` + manual prefix. SKIP: pino/winston-style structured JSON logging for production servers; browser console (this writes to `process.stdout` by default).

Log

import { log } from "@mongez/copper";

log.info("Starting server on", 4000);
log.success("Build complete");
log.warn("Cache miss for", { key: "user:42" });
log.error(new Error("Database unreachable"));
log.debug("payload", payload);

Each call writes one line prefixed with a colored level symbol — ℹ info, ✔ success, ⚠ warn, ✖ error, • debug (with Windows ASCII fallbacks).

Default singleton

log is preconfigured: every level enabled, writing to process.stdout. Import and go.

createLogger(options)

Option	Default	Note
level	"debug"	Suppress lower priorities. Order: debug < info < success < warn < error
stream	process.stdout	Switch to process.stderr to keep warnings off piped stdout
levels	(built-ins)	Per-level { symbol, label, color } overrides

import { createLogger, colors, symbols } from "@mongez/copper";

const log = createLogger({
  level: "warn",                       // hide debug/info/success
  stream: process.stderr,
  levels: {
    error: { symbol: "💥", label: "BOOM", color: colors.redBright },
  },
});

Argument handling

Multiple args are joined by space. Each arg is stringified:

• string → as-is
• Error → error.stack ?? error.message
• everything else → JSON.stringify(value)

log.info("port", 4000, { secure: true });
// ℹ port 4000 {"secure":true}

log.error(new TypeError("nope"));
// ✖ TypeError: nope
//     at ...

Level filtering

const log = createLogger({ level: process.env.QUIET ? "warn" : "debug" });
log.debug("verbose stuff"); // hidden when QUIET=1
log.warn("still shown");

When to reach for log vs console

• Use log for CLI tooling output where colored levels improve scannability.
• Use console (or a real logger like pino) for server / production logging where you need structured JSON, timestamps, or transports.
• Use process.stderr.write directly when you want zero ANSI formatting — log always emits its symbol prefix.